Wicket messes uo the encoding of strings from Javascript

It seems the character encoding your application uses does not support some of the sent characters.

Make sure you use a good charset in Wicket's RequestCycleSettings. By default it is UTF-8, but your application may have changed it.

In addition if you use some old version of a Servlet container then you may need to use a Servlet Filter around Wicket Filter that sets the character encoding on the HttpServletRequest. A quick googling for "Servlet filter character encoding" gives this good example: https://stackoverflow.com/a/11100412/497381.

public class CustomCharacterEncodingFilter implements Filter {

  public void init(FilterConfig config) throws ServletException {
  }

  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) 
                                                   throws IOException, ServletException {
    request.setCharacterEncoding("UTF-8");
    response.setCharacterEncoding("UTF-8");
    chain.doFilter(request, response);
  }

  public void destroy() {
  }

}